I am trying to import a module generated with emscripten as a es6 module. I am trying with the basic example from emscripten doc.
This is the command I am using to generate the js module from the C module:
emcc example.cpp -o example.js -s EXPORTED_FUNCTIONS="['_int_sqrt']" -s EXTRA_EXPORTED_RUNTIME_METHODS="['ccall', 'cwrap']" -s EXPORT_ES6=1 -s MODULARIZE=1
The C module :
#include <math.h>
extern "C" {
int int_sqrt(int x) {
return sqrt(x);
}
}
Then importing the generated js module:
<!DOCTYPE html>
<html lang="en" dir="ltr">
<head>
<meta charset="utf-8">
<title>Wasm example</title>
</head>
<body>
<script type="module">
import Module from './example.js'
int_sqrt = Module.cwrap('int_sqrt', 'number', ['number']);
console.log(int_sqrt(64));
</script>
</body>
</html>
This is failing because cwrap is not available on the Module object:
Uncaught TypeError: Module.cwrap is not a function
I am trying to import a module generated with emscripten as a es6 module. I am trying with the basic example from emscripten doc.
This is the command I am using to generate the js module from the C module:
emcc example.cpp -o example.js -s EXPORTED_FUNCTIONS="['_int_sqrt']" -s EXTRA_EXPORTED_RUNTIME_METHODS="['ccall', 'cwrap']" -s EXPORT_ES6=1 -s MODULARIZE=1
The C module :
#include <math.h>
extern "C" {
int int_sqrt(int x) {
return sqrt(x);
}
}
Then importing the generated js module:
<!DOCTYPE html>
<html lang="en" dir="ltr">
<head>
<meta charset="utf-8">
<title>Wasm example</title>
</head>
<body>
<script type="module">
import Module from './example.js'
int_sqrt = Module.cwrap('int_sqrt', 'number', ['number']);
console.log(int_sqrt(64));
</script>
</body>
</html>
This is failing because cwrap is not available on the Module object:
Uncaught TypeError: Module.cwrap is not a function
2 Answers
Reset to default 15As you're using MODULARIZE, you have to make an instance of the Module first.
import Module from './example.js'
const mymod = Module();
const int_sqrt = mymod.cwrap('int_sqrt', 'number', ['number']);
console.log(int_sqrt(64));
You could also try the MODULARIZE_INSTANCE option.
You may need to wait for it to finish initialising - I'm not sure when the function is so simple. That would look like this:
import Module from './example.js'
const mymod = await Module();
const int_sqrt = mymod.cwrap('int_sqrt', 'number', ['number']);
console.log(int_sqrt(64));
What worked for me:
emcc compile options:
emcc latuile.cpp bombix.cpp -o latuile-origine.js -s EXPORTED_FUNCTIONS='["_latuile","_bombix"]' -s EXPORTED_RUNTIME_METHODS='["ccall","cwrap"]' -s ALLOW_MEMORY_GROWTH=1 -s EXPORT_ES6=1 -sMODULARIZE -s EXPORT_NAME="createMyModule"
Where latuile and bombix are the names of the C++ functions I want to call.
At the bottom of the produced file latuile-origine.js, I read:
export default createMyModule;
Then in the Javascript module that imports from latuile-origine.js, I have (notice the 'default' keyword):
import {default as createMyModule} from "./latuile-origine.js";
var Module;
function clientFunction()
{
...
const bombix = Module.cwrap("bombix","string",["string","string","string","string"])
const jsonResponse = bombix(rectdim, translations, sframe, slinks);
...
}
window.main = function main()
{
createMyModule().then(function(mymod){
Module = mymod;
});
}